ul li {
    list-style-type: none;
    cursor: pointer;
}

.content {
    padding: 0 10px;
    width: calc( 100% - 280px);
    float: left;
}


/* index.html */

.login {
    width: 150px;
    margin: 80px auto;
}


/* main.html */

.top {
    width: 100%;
    height: 50px;
    position: fixed;
    background: grey;
    color: white;
    clear: both;
    top: 20px;
}

.top li {
    float: left;
    padding: 0 5px;
}

.main {
    margin: 80px auto;
    overflow-y: scroll;
}

.tree {
    display: block;
    float: left;
    width: 250px;
    border: 1px solid black;
    height: 100%;
    min-height: 400px;
    overflow-x: scroll;
}

.right {
    display: block;
    float: left;
    padding: 30px;
    width: calc(100% - 350px);
}

.container {
    display: flex;
    flex-direction: row;
    justify-content: start;
}

.container>div {
    display: block;
}


/* register page */

.register {
    width: 300px;
    margin: 0 auto;
}